"George Christensen posted a vulgar picture of him holding a hand gun, and making what he says is a joke about shooting people, and frankly guns aren't a joke and particularly in the wake of the massacre in the US only last week with 17 people shot dead, including children," Senator Hanson-Young said.

Senator Hanson-Young said she received an abusive email shortly after she criticised Mr Christensen's post on social media.